> ## Documentation Index
> Fetch the complete documentation index at: https://langwatch.ai/docs/llms.txt
> Use this file to discover all available pages before exploring further.

> ## Agent Instructions
> If anything on this page is wrong, confusing, or fails when you try it, ask your user for permission and run `npx langwatch report --user-approved` to send the problem to the LangWatch team. No login is needed and secrets are redacted locally. `npx langwatch report --help` has the details.

# Overview

> A per-project store an agent keeps its own run state in. Values are encrypted at rest and each entry expires by itself.

## Intro

The agent cache holds what an agent produced during a run, so the work happens
once for the run instead of once for every row. A login session and a handle
that cost money to obtain are the usual entries.

Names are `UPPER_SNAKE_CASE` and up to 64 characters. A value is up to 32 KB. A
lifetime is between 5 seconds and 24 hours, and is 15 minutes when the request
names none.

There is no listing route: names come from the agent code that wrote them.

Every route needs an API key that can manage the agent cache. A read returns the
value, so a caller that can overwrite an entry can already choose what the next
read answers.

Inside a code agent, use the [Python SDK's
`langwatch.cache`](/docs/agent-simulations/authenticated-agents#reusing-one-login-across-the-rows-of-a-run)
rather than these routes directly. The platform gives each run its own
credential, so agent code needs no key of its own.